Effect of Electrolytic Medium on the Electrochemical Reduction of Graphene Oxide on Si(111) as Probed by XPS

Abstract

The wafer-scale integration of graphene is of great importance in view of its numerous applications proposed or underway. A good graphene–silicon interface requires the fine control of several parameters and may turn into a high-cost material, suitable for the most advanced applications. Procedures that can be of great use for a wide range of applications are already available, but others are to be found, in order to modulate the offer of different types of materials, at different levels of sophistication and use. We have been exploring different electrochemical approaches over the last 5 years, starting from graphene oxide and resulting in graphene deposited on silicon-oriented surfaces, with the aim of understanding the reactions leading to the re-establishment of the graphene network. Here, we report how a proper choice of both the chemical environment and electrochemical conditions can lead to a more controlled and tunable graphene–Si(111) interface. This can also lead to a deeper understanding of the electrochemical reactions involved in the evolution of graphene oxide to graphene under electrochemical reduction. Results from XPS, the most suitable tool to follow the presence and fate of functional groups at the graphene surface, are reported, together with electrochemical and Raman findings.

Functionalization of Graphene by π–π Stacking with C60/C70/Sc3N@C80 Fullerene Derivatives for Supercapacitor Electrode Materials

“…Expected intensity ratio of 2:1 and splitting of 4.6 eV were observed [47] and are clearly attributed to scandium atoms bound to nitrogen and trapped inside of C80 fullerene core. Introduction of fullerene malonates onto graphene surface was clearly confirmed by the presence of higher binding energy signals associated with carbonyl carbon atoms from ester functional groups, observed at 288.6-288.9 eV [44]. Another signal that proves successful functionalization of graphene are π-π satellites observed in all fullerene modified samples, with binding energies of 290.5-290.7 eV [45].…”

“…It can be attributed to the endohedral nature of the corresponding fullerene core and strong interactions of C80 fullerene carbon atoms with trapped Sc3N molecules, especially as this fullerene was reported to follow the ionic model Sc3N 6+ @C80 6− [42,43]. Introduction of fullerene malonates onto graphene surface was clearly confirmed by the presence of higher binding energy signals associated with carbonyl carbon atoms from ester functional groups, observed at 288.6-288.9 eV [44]. Another signal that proves successful functionalization of graphene are π-π satellites observed in all fullerene modified samples, with binding energies of 290.5-290.7 eV [45].…”

One-pot carboxyl enrichment fosters water-dispersibility of reduced graphene oxide: a combined experimental and theoretical assessment

“…AA is a known reducing agent toward the epoxide and diol functional groups of GO, with no reported effects on the carboxyl functionalities. 32,33,51,60…”

“…12b) of C-RGO in the region of D and G bands, shows an increased I D / I G ratio (0.92) compared to C-GO (0.86), a trend which is fully coherent with reduction of a graphene oxide based material. 33,51,52…”

“…XPS spectroscopy is a fundamental tool for the investigation of the surface functionalities of GO-based materials. 33,48,51,52,56,57 The deconvoluted C 1s spectra of GO and its carboxylated derivatives are reported in Fig. 7 (see Table S1 † for details).…”